University of Windsor Scholarship at UWindsor OSSA Conference Archive OSSA 11 May 18th, 9:00 AM - May 21st, 5:00 PM Arguments from Expert Opinion and Persistent Bias Moti Mizrahi Florida Institute of Technology - Melbourne Follow this and additional works at: https://scholar.uwindsor.ca/ossaarchive Part of the Philosophy Commons Mizrahi, Moti, "Arguments from Expert Opinion and Persistent Bias" (2016). OSSA Conference Archive. 78. https://scholar.uwindsor.ca/ossaarchive/OSSA11/papersandcommentaries/78 This Paper is brought to you for free and open access by the Conferences and Conference Proceedings at Scholarship at UWindsor. It has been accepted for inclusion in OSSA Conference Archive by an authorized conference organizer of Scholarship at UWindsor. For more information, please contact [email protected]. Arguments from Expert Opinion and Persistent Bias MOTI MIZRAHI School of Arts & Communication Florida Institute of Technology 150 W. University Blvd., Melbourne, FL 32901 USA [email protected] Abstract: Accounts of arguments from expert opinion take it for granted that expert judgments are reliable, and so an argument that proceeds from premises about what an expert judges to a conclusion that the expert is probably right is a strong argument. In my (2013), I considered a potential justification for this assumption, namely, that expert judgments are more likely to be true than novice judgments, and discussed empirical evidence suggesting that expert judgments are not more reliable than novice judgments or even chance. In this paper, I consider another potential justification for this assumption, namely, that expert judgments are not influenced by the kinds of cognitive biases novice judgments are influenced by, and discuss empirical evidence suggesting that experts are vulnerable to pretty much the same kinds of cognitive biases as novices. If this is correct, then the basic assumption at the core of accounts of arguments from expert opinion remains unjustified. Keywords: arguments from expert opinion; cognitive bias; decision heuristics; expert performance; persistent bias 1. Introduction In my (2013) paper, I argue that arguments from expert opinion are weak arguments. An argument from expert opinion is an argument one makes when there is no reason to believe that p other than the fact that an expert judges that p is the case and the expert’s judgment is taken as evidence that (probably) p. To say that such an argument is weak is to say that an expert’s judgment that p does not make it significantly more likely that p. This claim is supported by experimental studies on expert performance. Such studies show that expert performance is often no better than the performance of novices or even chance. My (2013) paper received some attention from argumentation theorists, and for that, I am very grateful. Unfortunately, I think that the attention was misplaced. That is to say, instead of focusing on what I take to be the main challenge my paper raises, namely, how to justify the assumption that expert judgments are a reliable source of evidence, which every account of arguments from expert opinion takes for granted, those who responded to my paper have chosen to focus on my formulation of arguments from expert opinion and accuse me of “refusing to countenance the possibility that other premises of the form of the argument from expert opinion need to be taken into account” (Walton 2014, p. 142),1 on my examples and accuse me of being a “radical sceptic about expertise” (Seidel 2014, p. 215),2 and even on objections raised against my argument (rather than my own argument) and accuse me of being “confused” (Hinton 2015, p. 542). However, as I have argued at length in my (2013, pp. 67-72), virtually all formulations of arguments from expert opinion, including Walton’s (2006, p. 750), take it for granted that an expert’s judgment that p counts as (defeasible) evidence for p. No matter how many premises an argumentation scheme for arguments from expert opinion contains, or how many critical 1 See also Walton (2016, pp. 117-144). 2 See also Jackson (2015, pp. 227-243). Bondy, P., & Benacquista, L. (Eds.). Argumentation, Objectivity, and Bias: Proceedings of the 11th International Conference of the Ontario Society for the Study of Argumentation (OSSA), 18-21 May 2016. Windsor, ON: OSSA, pp. 1-8. MOTI MIZRAHI questions are added to that argumentation scheme (Walton et al 2008, pp. 14-15), the basic assumption is that expert judgments count as (defeasible) evidence for propositions.3 After all, that is precisely what an argument from expert opinion is supposed to be; that is, an inference from what an expert judges to be the case to the conclusion that what the expert judges to be the case probably is the case. The question I raised in my (2013) is this: Why assume that an expert’s judgment that p is (defeasible) evidence for p? In other words, according to Goodwin (2011, p. 293), “the appeal to expert authority is a blackmail and bond transaction […] that brings the background norm of respect for expertise to bear in a particular situation” (emphasis added). But why should we respect expertise at all (let alone accept such respect as a “background norm”)? In my (2013) paper, I consider the following response to this question concerning the justification for the “background norm of respect for expertise”: The assumption that an expert’s judgment that p is (defeasible) evidence for p is warranted only if expert judgments are more reliable (i.e., more likely to be true) than novice judgments. In other words, we should respect expertise because experts are more likely to get things right than novices are. As I argue in my (2013, pp. 63-65), however, this response is inadequate because expert judgments are not more likely to be true than novice judgments. Since the question whether expert judgments are reliable or not is an empirical question, I have looked at experimental studies aimed at testing expert performance. As I discuss in my (2013, pp. 63-65), many experimental studies on expert performance show that experts often fail to perform better than novices on tasks such as decision-making, forecasting, diagnosing, and the like. In fact, expert judgments are often no more likely to be true than false, which means that, statistically speaking, they are not significantly better than guessing. Based on such empirical evidence derived from experimental studies on expert performance, I (2013, pp. 58-59) have argued as follows: 1. An expert’s judgment that p is (defeasible) evidence for p only if expert judgments are reliable. 2. It is not the case that expert judgments are reliable. Therefore, 3. It is not the case that an expert’s judgment that p is (defeasible) evidence for p. In other words, if there were evidence that expert judgments are reliable (or at least more reliable than novice judgments), then that would have been a strong reason to think that experts judgments are (defeasible) evidence for the truth of such judgments. Since there is no evidence that expert judgments are reliable (in fact, there is evidence to the contrary, i.e., that expert judgments are not more reliable than novice judgments), there is no reason to think that expert judgments are (defeasible) evidence for the truth of such judgments. Accordingly, the justification for the “background norm of respect for expertise” cannot be that expert judgments are reliable, since experimental studies suggest that expert judgments 3 In Wagemans’ (2011, p. 337) “scheme for argumentation from expert opinion,” this basic assumption is stated as follows: “Accepting that O is asserted by E renders acceptable that O is true or acceptable.” 2 MOTI MIZRAHI are not more reliable than novice judgments. In fact, there is empirical evidence that expert judgments are often not significantly more likely to be true than false. In this paper, I will consider another potential response to the question concerning the justification for the “background norm of respect for expertise.” This response goes as follows: The assumption that an expert’s judgment that p is (defeasible) evidence for p is warranted only if experts are not susceptible to the kinds of cognitive biases that novices are susceptible to. In other words, we should respect expertise because, unlike novices, experts are immune to cognitive biases, such as confirmation bias, framing effects, order effects, and the like. I will argue that this response, too, is inadequate, since experimental studies on cognitive biases show that experts are vulnerable to pretty much the same kinds of biases as novices. If this is correct, then the “background norm of respect for expertise,” the basic assumption at the core of arguments from expert opinion according to which experts judgments are a reliable source of evidence, remains unjustified. 2. Are experts immune to bias? I take it as uncontroversial that, from an epistemic point of view, we should not trust or respect sources of evidence that are not reliable. My critics would probably agree with that. For example, Seidel (2014, p. 195) writes that he has “no objection to this latter claim [namely, that “arguments from expert opinion are weak arguments unless the fact that E says that p makes it significantly more likely that p is true” (Mizrahi 2013, p. 58)] since it just is a formulation of the close connection between the reliability and the epistemic trustworthiness of an epistemic source.” In my (2013) paper, I have discussed experimental studies that provide empirical evidence against the claim that expert judgments are reliable (either significantly more likely to be true than novice judgments or significantly more likely to be true than false). The aforementioned empirical evidence notwithstanding, some might still think that we should trust or respect expert judgments because, unlike the judgments of novices, the judgments of experts are not subject to cognitive biases.